Institute for Electrical and Electronics Engineers (IEEE) standard 802.1Q is a virtual local area network (VLAN) tagging networking standard that allows multiple bridged networks to transparently share physical network links without any leakage of information between networks. IEEE standard 802.1Q includes the encapsulation protocol used to implement VLAN tagging over Ethernet networks, and defines the meaning of a VLAN with respect to bridging at the Media Access Control (MAC) layer. Multiple MAC Registration Protocol (MMRP) is a protocol used in IEEE standard 802.1Q-based customer networks to build multicast spanning trees which limit the multicast traffic to the interested parties. IEEE standard 802.1ak may be implemented in conjunction with MMRP to allow for dynamic registration and deregistration of VLANs on ports in a VLAN bridged network.
Generally, multiple 802.1Q networks of a single customer may be interconnected by an IEEE standard 802.1AD service provider core network. Existing 802.1AD service provider core networks, which connect 802.1Q customer networks, use peering or tunneling to handle customer layer 2 control traffic that transits between customer networks via the service provider core network. If tunneling is used to handle the customer layer 2 control traffic, customer MMRP registrations are transparently tunneled by the 802.1AD service provider core network so that the customer networks can maintain end-to-end multicast registrations. However, since the service provider core network is not participating in the customer MMRP registrations, customer multicast data units are unnecessarily flooded throughout the entire service provider core network. If peering is used to handle customer layer 2 control traffic, the service provide edge bridge participates in the customer MMRP registration, and converts the MMRP registrations from the customer VLAN (CVLAN) domain into the SVLAN assigned for that customer. This approach limits the flooding in the service provide core network but, since provider edge bridges are combining all MMRP registrations from multiple CVLANs into a single SVLAN, all of the CVLAN-based multicast trees in the customer network will converge into a single SVLAN-based multicast tree. The tunneling approach, therefore, does not utilize the customer network MMRP registrations in the service provider network thereby causing excessive flooding in the service provider network. The peering approach, however, solves the excessive flooding problem, but at the cost of interfering with the customer MMRP operations.